Heading Levels – Your PDF’s Roadmap
Heading Styles and How They Help with Accessibility
Using headings correctly is a critical component in proper PDF tagging. For people using screen reading software, heading tags provide the same type of structural and navigational information that bookmarks provide to others. When headings are used correctly, people using assistive technology can more readily navigate to the section(s) in the document they want to read. In addition, they’re told organizational information, like whether that particular content is a sub-section of a bigger part.
Assigning Heading Levels Properly
When fixing heading levels in a PDF, there are a number of things to consider. First and foremost, headings should be used like an outline. The H1 (Heading One) tag is reserved for the Title of the document. Under the H1, H2s (Heading Two) are used for your “major sections” or chapters. Following these guidelines, Chapter 1, Chapter 2, and Chapter 3, for example, would all be placed in H2 tags. Then, if Chapter 1 has sub-sections, A, B, and C, for example, then those sub-sections would be in H3 (Heading 3) tags. When you get to Chapter 2 in the PDF, again, that tag would be an H2.
To be fair, there is some confusion, and some debate, around this topic. Without getting into too much complexity, we’ll address some common questions.
The H1 Controversy
Some people think you should use the tag for the Title of the document and then put the chapters in H1 tags (as opposed to H2 as recommended in the previous paragraph). One problem with this approach is that it creates an immediate failure of certain PDF accessibility standards. Specifically, PDF/UA states that both H and H# tags should not be used in the same PDF. Another argument maintains that the document can have multiple H1 tags – for the title as well as the chapters, for example. The problem with this, however, is that when screen readers announce the H1 tags throughout the document, the implication is that everything tagged as an H1 is at the same hierarchical level. This could lead people to the conclusion, and the confusion, that instead of listening to a document with a title and subsections (or chapters), what they are really listening to is, perhaps, a series of documents all merged into one PDF file. Another thing to be aware of, which happens more often in Word and HTML, is using a particular Heading (or Style in Word) because it automatically gives a certain appearance (font, bold, etc.), rather than using the correct heading level (or Style), and then changing the look for the desired visual effect.
Pro-tip for Document Authors Using Microsoft Word
Correctly using the Styles provided in Word helps not only to more quickly and accurately insert a Table of Contents, but also helps establish the structural organization in the PDF created from that Word document. In addition, choosing a particular Heading Style in Word doesn’t “lock you in” to its appearance. After you choose the necessary Style, you can modify it so that it looks the way you want. What’s important is that you’re using the correct Heading for your content.